至于电子邮件输入表单，您可以使用任何用于自定义字段的插件（我使用Advanced Custom Fields 或Custom Content Type Manager ) 或添加您自己的元框（tutorial ).

要将电子邮件发送到作为自定义字段插入的地址，请使用以下代码
自定义字段命名为email_warn.

过滤器wp_mail_content_type 为电子邮件启用html内容
和add_attachment 如果自定义字段已定义且为有效电子邮件，则将在每次上载时触发，提取父ID并发送电子邮件

add_filter( \'wp_mail_content_type\', \'wpse_20324_mail_html\' );
add_filter( \'add_attachment\', \'wpse_20324_post_upload\' );

function wpse_20324_mail_html()
{
    return "text/html";
}

function wpse_20324_post_upload( $attachment_ID )
{
    $uploaded = get_post( $attachment_ID );
    $email = get_post_meta( $uploaded->post_parent, \'email_warn\', true );

    if( isset( $email ) && is_email( $email ) ) 
    {
        /**
         * The message will contain all post info about the uploaded file 
        */
        $vardump = print_r( $uploaded, true );
        $message = \'<pre>\' . $vardump . \'</pre>\';

        $headers = \'From: Test WPSE <[email protected]>\' . "\\r\\n";

        wp_mail( $email, \'subject\', $message, $headers );
    }
}